Chile is usually regarded as one of the most orderly and stable countries in South America, so the images that have come out of the capital, Santiago, in recent days have been especially shocking.

Thousands of high school and university students have marched through the capital's streets, as well as those of other major cities, demanding a radical overhaul of the education system.

Invariably the demonstrations have ended in violent clashes between masked youths and police officers armed with tear gas and water cannon.

Shops and offices on Santiago's main thoroughfare, the Alameda, have been looted and destroyed.

We don't believe that school education should be a state monopolyFelipe Bulnes, Education Minister

The scenes have been reminiscent of the pro-democracy protests of the 1980s, when Chileans clashed with the forces of General Augusto Pinochet.

On one day alone, 4 August, more than 900 people were arrested in protests up and down the country and nearly 100 police officers injured.

The government estimated the cost of damage to public and private property in central Santiago at $2m (£1.2m).

Ordinary Chileans have staged nightly cacerolazos, or "saucepan protests", a form of dissent not seen since the Pinochet days.

They have poured on to the streets to bang pots and pans in support of the students and in opposition to the government.

Shabby schools

So, what is going on in Chile? Are the protests simply about education or do they reflect wider discontent with the government and the way the country is run? How and when are they likely to end?

Education is clearly not the only issue at stake, but it is certainly the main one.

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Demonstrations in the capital have been marked by violence

The student marches have been far bigger than those organised by other protest groups. On several occasions, they have drawn 100,000 people on to the streets.

At the heart of the students' anger is a perception that Chile's education system is grossly unfair - that it gives rich students access to some of the best schooling in Latin America while dumping poor pupils in shabby, under-funded state schools.

But Mario Waissbluth, a Chilean professor and national coordinator of the citizens' group Educacion 2020, says the figures tell only part of the story.

He says that of the 65 countries that participated in the PISA tests, Chile ranked 64th in terms of segregation across social classes in its schools and colleges. Only Peru has a more socially divided education system.

Prof Waissbluth describes this as "educational apartheid" and says it lies at the heart of the current unrest.

State vs private

Chile's secondary schooling takes three forms:

45% of pupils study in state schools

50% in voucher schools, where the government subsidises the pupil's education

The voucher schools are privately run and, in theory, can turn a profit, although many do not.

That means that over half the schools in Chile, as well as most of the universities, are, in effect, privately-run entities.

The protesters object to that and have called for an end to profit in education.

The government says that is unrealistic.

"We don't believe that school education should be a state monopoly," Education Minister Felipe Bulnes told the BBC.

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The students' demands enjoy support from other sectors of society

"The private sector has to play a role in it."

Jose Joaquin Brunner, an educationalist and former government minister, says that rather than scrapping the current system, Chile should try to emulate countries like Belgium and the Netherlands, which have a similar mix of state and privately-funded schools but without the deep inequalities that afflict Chile.

Whatever the solutions, most people agree that the education system is in a sorry state.

The Center of Public Studies (CEP), a local think tank, published a poll this month showing that more than a quarter of Chileans think education has deteriorated over the past 10 years and a further 45% think it has simply stagnated.

For some, this is a damning indictment of a country whose economy has expanded at 4% a year during that period, generating money that could have been ploughed into schools.

The student conflict has tarnished the government, according to opinion polls.

These suggest that only 10% of Chileans think the administration is handling education policy well, down from 32% late last year.

President Sebastian Pinera, Chile's first conservative leader for 20 years, has seen his approval ratings slump to 26%.

That is the lowest for any Chilean president since the return to democracy in 1990.

Broader complaints

While education is the main bone of contention at the moment, it is not the only one:

Environmentalists have marched against a plan to build a big hydro-electric plant in Patagonia

Copper miners have staged strikes

Gay rights campaigners have called for full gender equality

Transport workers have protested about job insecurity

Farmers have complained about the impact of the strong Chilean peso on exports.

Hardly a day goes by without someone marching down the Alameda.

"The unrest goes beyond education, even if education is the reason why it's suddenly burst into the open," said Mr Brunner.

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President Pinera has seen his popularity plummet from the the high of the San Jose miners' rescue

He believes Chile is paying the price for embracing a radical free market model that he describes as "more North American than European in tone".

"The model here is like the United States, with the markets left to run slightly wild, pervading every aspect of life, including education and health," he said.

"The end result is that people feel a deep sense of unease."

The current protests come as GDP growth is forecast at about 6% this year and unemployment is falling.

In the past, that might have kept Chileans happy and off the streets, but no longer.

The economic progress of recent years has raised expectations, and many Chileans say they now want social progress too.

That explains why so many people have joined the cacerolazos and why the students enjoy broad support.

It is difficult to see an imminent end to the wave of protests or indeed the violence that invariably accompanies them.

The students and government are poles apart and cannot even agree on the route that the marches should take.

Some observers are calling this the Chilean Winter. For now, the warmer days of the southern spring feel a long way away.